1. Technical Field
The present invention relates to a connection constitution of signal lines of an electric apparatus and particularly relates to an electric apparatus which has a connection constitution including a multi-stage hinge.
Priority is claimed on Japanese Patent Application No. 2009-016779, filed Jan. 28, 2009, the content of which is incorporated herein by reference.
2. Background Art
For an electric apparatus such as a mobile terminal, various kinds of numeric data and character data input via key operations are necessary, for example, numeric characters, alphabet, Japanese Kana characters and Chinese characters. Due to such a precondition, such an electric apparatus conducts conversion operations by using each key to which multiple key functions are assigned, and therefore, operations of the electric apparatus are complex. Therefore, an electric apparatus having multiple key panels has been desired to improve operability.
On the other hand, a mobile electric apparatus is required to be small, thin and light so as to be convenient for carrying. Due to such a requirement, an electric apparatus having a stowaway key panel is provided. However, in a case of the stowaway key panel, there is a problem of a connection constitution of signal lines at a hinge portion.
For example, a connection constitution of signal lines disclosed in Patent Document 1 has a cavity portion inside a hinge portion of a cellular phone which is a flip phone, and wirings are arranged inside the cavity portion to have electrical connection between the chassis. In a concrete case, as shown in FIG. 9, a first chassis 901 including a display portion and a second chassis including a key operation portion, for example, buttons are rotatably connected to each other via a hinge portion 903. In a cavity portion 905 formed along a rotation axis of the hinge portion 903, a line 904 electrically connects both the first chassis 901 and the second chassis 902. The line 904 has a spiral portion 904a which has a curled shape to prevent damage, for example, breaking of the line due to open/close operations of the first chassis 901 and the second chassis 902 (see Patent Document 1).
In such a prior technique, a diameter of the spiral portion 904a is changed so as to absorb stretch of the line 904 due to open/close operations of the first chassis 901 and the second chassis 902. In other words, a countermeasure of breaking of the line is applied to ease the stress which is caused on the line 904 upon open/close operations. In general, for example a cable and a flexible substrate are applied to the line 904. Particularly, the flexible substrate has fine wiring patters formed on a film material and has flexibility, and therefore, the flexible substrate is preferred and used for arranging the line 904 inside a limited space, for example, the hinge portion 903. In other words, for example, when the first chassis 901 and the second chassis 902 are rotated around the hinge portion 903, a shape of the above-described flexible substrate can be modified or curved to some extent in accordance with such rotation, and it is possible to provide a countermeasure for breaking of the line 904.
Further, in a hinge constitution including a pair of parallel axes described in Patent Document 2, a hinge portion 903 is set between a first chassis 901 and a second chassis 902 as shown in FIGS. 10A and 10B. A line 904 connects the chassis 901 and the chassis 902 while passing through the hinge portion 903. For example, a discrete line or a fine coaxial line is used as such a line 904. Particularly, a fine coaxial line accepts curves with various angles and changes shapes in accordance with rotation of the first chassis 901, second chassis 902 and the hinge portion 903 that are connected, and therefore, it is possible to provide a countermeasure for breaking of the line 904.
Further, in a constitution of a hinge portion of a mobile terminal described in Patent Document 3, a cylindrical shape portion is included in each of chassis that are connected by using a hinge. While the cylindrical shape portions are combined, both a hinge unit and a support portion are inserted from one end, and the hinge portion is constituted in such a manner. Further, notch portions are provided which, when the cellular phone is opened, appear on surfaces of the same side, and a path through which a flexible printed substrate is lead is formed when the notch portions face each other. Such a hinge portion constitution described in Patent Document 3 is generally known as a hinge portion of a cellular phone in which a line is lead through the hinge portion formed by a portion of the chassis, and not lead inside a hinge.    [Patent Document 1] Japanese Patent Application, First Publication No. 2006-93461    [Patent Document 2] Japanese Patent Application, First Publication No. 2006-64000    [Patent Document 3] Japanese Patent Application, First Publication No. 2008-271352    [Patent Document 4] Japanese Patent Application, First Publication No. H05-211464